Chain Noise on new build

Hi,
It's been more than 20 years since I rode a fixed gear so have no memory as to whether this is normal or not! Maybe you could help...
Sram Omnium 48t, 18t Halo Fix-g Cog, KMC Z510HX.
Chain line is perfect. Contrary to what I've read almost everywhere, the current Omniums have a 45mm chain line. I wonder if they did this intentionally to increase compatibility with frames.?.?.
The fix-g cog position is adjusted accordingly and chain line is perfect.
After a couple of hundred miles I still get a bit of noise. Kind of like a front derailleur rubbing a bit on an extreme chain line.
Does it just need more bedding in or should I expect a little noise? Ta.

Could you post a sample of the noise? or video would help

Is it a carbon frame. I have had it in the past where a normal sounding chain can be exceptionally loud as it resonates through the carbon.

Should be able to sort something out tonight. Cheers

No; aluminium frame, carbon fork.

Were all the parts new ? sprocket, chain and chainring. A worn sprocket and a new chain can make a similar sound to the one you described.

I've also had a few noise issues with 1/8 chains and 3/32 sprockets but it shouldn't be that bad.

Thanks. Everything brand new and 1/8".

Not the best quality but hopefully you'll be able to hear this. The volume improves when I let the pedals spin of their own accord and hold the mic closer.

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• Chain.m4a

Hmm odd, how tight are you running the chain ? Does it get worse when your out of the saddle ?

I would say it's much the same seated or not. I think it could do with a touch more lube so I'll try that next ride.
Chain is perhaps a shade on the tight side but being new I don't think I'd want it looser. You can just see a small bit of droop in the middle above the chainstay...

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M4a file didn't load for me?

Sounds tight to me.

That cog might be a little odd - can you try with another?

but being new I don't think I'd want it looser.

I don't understand your reasoning on this point.

Apart from the fact that a tight chain will be noisy, it and both sprockets will wear faster.

Having said that, Thuekr is right: some chain and sprocket combinations don't work well.

Put the bike on a workstand or turbo and look closely at the way the chain joins and leaves the sprocket.

Thanks.
Well I figured that as it beds in it would become fractionally looser still.
Maybe it's a bit too tight; I don't remember setting the chain so loose in the past but no worries.
I do have another couple of spare Halo cogs. I could also swap the wheel as I have a no brand screw on cog on another wheel.

Thanks for all the suggestions. I'll get it on the turbo and have a play around.

I'd say chain ring is ovalised as it seems you have a tight and even tightererer spot, find tight spot adjust chain tension to suit said spot and forget about it.

Really? I thought Omniums were supposed to be pretty good in this respect. I might get it up on a lathe and do some measuring.

From my personal experience you almost nearly have a tight spot. Just ride it out.

Or not

The ring itself could be round but just not seated exactly right on the spider so sits off centre creating a cam.

I had a similar noise with a new chain in conjunction with existing chainring and cog. It soon bedded in after a couple of 40km rides and its fine now.

I had an all new and matching drivetrain once that gave a horrendous racket which was worse when putting force through the pedals, just like you. The chain was too tight, just slack it off a bit, solved my problem.

Quick update folks; got the omniums mounted in a lathe using soft jaws on the GXP spindle.
Really impressed. The crank arm makes measuring awkward and I don't have access to most conventional measuring tools. I tried to rig up a laser pointer but it failed to provide anything meaningful. Instead I just used a vernier caliper and took some random measurements to compare various points on the chainring from the centre of the spindle.
Suffice to say the chainring teeth to spindle centre relationship is at least as precise as the (much more expensive) track specific chainring I have so I've total confidence in that now.
The omnium ring also runs true. So it's flat and round! all good there.
I now believe most of the noise is coming from the halo cog. The only way I could get virtually silent running was to have the chain so loose as to be dangerous.
As such, I've backed it off a little, added some extra lube and I'm calling it done.

Just built up a carbon frame , carbon rims . New sproket , cog and chain ...
It's so loud ! I have a friend who's a builder and he has a laser to check everything is in line, but I may try different chains if everything is all in line perfect

I've a good few thousand miles under my belt since I posted this thread and got through a fair handful of cranks / chainrings / cogs /chains.
In my experience excessive noise (as in noisy enough to actually hear when riding) will mainly come from either lack of lubrication or too tight a chain.
Chainline can be out by a fair bit without contributing massively to noise. You do get certain chainrings / cogs / chains that just happen to be noisier than others.
If you can rule out any of those then I guess your carbon frame could be amplifying the noise but personally I've never used a carbon frame for fixed gear.....